In a digital filter, a sample and hold circuit holds sequentially input data, and the multiplier data is accumulated. The held data is transferred to a sequential following sample hold circuit and input to a different multiplier.
Conventionally, in a digital filter, digital data is held and transferred, and a hold error may be ignored. On the other hand, analog calculation needs analog data, and a hold error can not be ignored. However, a sample and hold circuit for holding and transferring analog data is not known.